Roll-making machines in the paper industry can comprise a support roll which can be perforated and internally subjected to vacuum to hold the paper web against this roll as the paper web is transported to a roll of paper being formed on the support roll at one or more stations.
In general, the paper web is fed from below to the support roll and must be brought into contact with the underside thereof so that it can be entrained by rotation of the support roll to the roll-making station.
Problems are encountered whenever a new paper web must have its leading end fed to the support roll.
Usually the guide path for the paper web lies beneath the floor above which the roll-making elements of the machine are disposed. To feed a new leading end of a paper web, upon replacement of a supply roll or upon tearing of the web, it is usually necessary to manually lift the leading end of the web and place it upon the underside of the support roll in a time-consuming operation.
When the machine is equipped with longitudinal slitters for subdividing the paper web into a plurality of strips, the slitting blades generally engage the web from opposite sides and at least one of these blades can be moved away from the path of the web to permit the leading end of the new web to be fed upwardly from the paper feed path below the floor, through an opening in the floor to meet the underside of the support roll.
Thereafter the paper web is advanced by the support roll which is provided with suction openings and is subjected to subatmospheric pressure as described. A paper roll-making machine having a support roll of this type with feeding of the paper web from below is described in German patent DE-PS 31 02 894.
It is known to facilitate the feed of the web in the region below the support roll from German open application DE-OS 31 17 094. In this system the leading end of the web is fed with the aid of compressed air utilizing a table which can be raised and lowered and serves to guide the web. With this means, the leading end of the web is pressed against the underside of the support roll. This system has not been found to be fully satisfactory.